Folding bore sight



Feb. 16, 1954 R. FLANAGAN FOLDING BORE SIGHT Filed Feb. 15, 1952 Ilm.

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Patented Feb. 16, 1954 FOLDING BORE SIGHT Robert Flanagan, Houston,Tex., assignor to the t United States of America as represented by theSecretary of the Army Application February 15, 1952, Serial No. 271,840

(Cl. :i3- 46) (Granted under Title 35, U. S. Code (1952),

sec. 266) 6 Claims.

` The invention described herein may be manufactured and used by or forthe Government for governmental purposes Without the payment of anyroyalty thereon.

This invention relates to bore sights for cannon, rocket launchers andthe like. The primary object of the invention is to provide an easilyportable folding bore sight for insertion in the breech of the weaponand employed in conjunction with a reticle device mounted on the muzzle,whereby the regularly provided weapon sights can be adjusted to properrelation with the axis of the bore.

Another object of this invention is to provide a bore sight which isvery easy to mount in opperative position and which requires noadjustment.

Another object of the invention is to provide a bore sight which can beused with many different types of complementary sights at the other endof the barrel being tested and adjusted.

A last object to be mentioned specifically is to provide a bore sightwhich is economical and practicable to manufacture, rugged and durable,as well as completely reliable and eflicient in use.

With these objects definitely in view, this invention resides in thenovel construction, arrangement and combination of elements as ishereinafter described and claimed in the speciiication and illustratedin the drawing wherein:

Figure 1 is a longitudinal axial section of a barrel, broken to conservedrawing space, and having this bore sight mounted in the cartridgechamber and shown in vertical section, a reticle assembly in verticalsection being indicated in the muzzle;

Figure 2 is a transverse section taken on line 2-2 in Figure 1;

Figure 3 is a view, in perspective, of the bore sight folded forcarrying or storage; and

Figure 4 is a similar view showing the bore sight partially expanded.

In the drawing and specification similar characters of reference relateto similar or identical elements and portions.

Referring now to the drawing in detail, the bore sight, generallyindicated by the numeral I0, is adapted to be located in the cartridgechamber l2, where present, or in a corresponding breech end portion of abarrel having no enlargement or chamber. The sight is used with areticle assembly I6 fitted in the muzzle end I8 of the bore 20. Theassembly I6 may be of any suitable character but the cross hairs 22 oran equivalent apertured element and a carrying member 24 Will probablybe required. The reticle assembly I6 is mentioned herein merely toindicate the environment wherewith the subject matter of the instantinvention is used.

The bore sight l!) is comprised of an elongated center plate 26 and apair of arms 28 and 30 of equal length but shorter than said centerplate, both arms being pivotally secured to an intermediate portion ofthe center plate 2B by a grommet 32.

The grommet 32 itself comprises an eye piece or,` as illustrated,carries a centrally apertured disc 34 which functions as an eye piece,this disc 34 being pressed into the grommet or otherwise rigidly securedwithin the grommet by any suitable means.

The center plate has a bore engaging ear 30 and the arms 28 and 30 havesimilar ears 38 and 40. The ears are all equidistant from the pivotgrommet 32 and the ears 38 and 40 are adjacent to the longitudinal edgesof each of the arms 28 and 30. The said ears all extend beyond thecorresponding ends of said plate and arms, and said ears al1 extend inthe same sense, the ears 38 and 40 being disposed laterally of the ear36, as illustrated in Figure 3, when the bore sight is folded. In thisconnection it should be noted that the end portions 42 of the centerplate and the corresponding end portions 44 and 46 of the arms are allpreferably rounded to facilitate the folding operation and to make thefolded device slightly more compact.

Stops 48, comprising opposing lugs on an end portion 5t of the centerplate 20 remote from the ear 36, serve to limit the angular movement ofthe arms relative to the center plate as clearly illustrated in Figure2. An important structural feature of this invention resides in thearrangement of the stops or lugs 48 so that the center plate ismaintained in vertical position after the sight is operatively located.

The operation of this invention will be clearly comprehended from aconsideration of the drawing and the foregoing objects and description.In recapitulation it might be added that in inserting the bore sightinto the end of a barrel, the arms 28 and 30 may be allowed to falloutwardly while the center plate is held with the ear 30 contacting thetop of the bore or cartridge chamber and proper mounting of the boresight is then automatically achieved. By sighting through the apertureddisc 34 and the cross hairs 22, upon a star or some other distantobject, and adjusting the weapon sights on the same object, perfect 3alignment of the barrel and sights can be achieved. The ease with whichthe bore sight I9 can be placed in operative position, removed, andcollapsed for carrying or storage will be readily appieciated.w n

Minoi` variation 'troni the illstratd for-in of this invention may beresorted to as specio facilities for manufacture and use shall dictate,al-l within the scope of the appended claims.

I claim:

1. A bore sight comprising an elongated center plate, a pair of similararms, a pivotally securing the arms to said plate, sai'd plate and armshaving bore-engaging elements all equidistant from said grommet, the -losig-ht being collapsible by pivoting the arms into substantial alignmentwith the center plate, and means on said elongated ce'nt'fi plate t lildthe arms in operative `or extended position each arm forming an obtuseangle with said center :pl-EWE'.

2i. Ab'oe sight according to claim 1 'and Wheresaid means :comprisesstops on said center 5. A bore sight comprising an elongated centerplate, a pair of similar arms, a grommet pivotally securing the arms tosaid plate, said plate and arms having bore engaging ears at the distalends thereof, said ears being equidistant from the v'said glorfxmt, thebore sight being"l collapsible by rotating the said arms into alignmentwith the said center plate, and stops on said 'center plate to hold thesaid arms in extended position ''ach forming an obtuse angle with saidcenter plate.

'61. 'sighting' d'i'li'e for use in the bore of a Weapon `:(:iiifisiigan elongated center plate, a pair of similar arms, a grommet pivotallysecuring the `"ar-rhs', to said plate, said plate and arms having boreengaging ears at the distal ends tlrf, said ears being equidistant fromsaid grommen, said g'mmet comprising an eye piece for sighting throughsaid bore, the device being collapsible by rotating -the said arms intoalignment with the said center plate, and stops on said center plate tohold the sai-d arms in ex'- tended position each forming an obtuse anglewith said center plate.

ROBERT FLANAGAN.

References Cited in the file of this patent FOREIGN PATENTS Nitrate;canary pare l172822 Great Britain nee. 22J 1921 313,728 italy aan. 4,1934

